Effect of Natural Weathering Processes on Size and Density Compositions of Bituminous Coal

Abstract

It is well-known that natural weathering processes can change the surface properties of coal. The carbon content on the coal surface can be reduced, while the oxygen content can be increased, by natural weathering processes. However, there is little direct and deep research into the effect of natural weathering processes on the size and density compositions of coal. In this investigation, the changes in the size and density compositions of bituminous coal before and after natural weathering processes were discussed. X-ray photoelectron spectroscopy and scanning electron microscopy measurements were used to explain these changes in micro aspects. Throughout this paper, both the size and density compositions of bituminous coal could be affected by natural weathering processes. Natural weathering processes not only reduce the coal particle size but also increase the coal particle density.

Investigation of the Coal Oxidation Effect on Competitive Adsorption Characteristics of CO2/CH4

“…An amorphous cell containing 16 optimized coal molecular structures is established, and molecular dynamic simulation is conducted to ensure the configuration is closer to the true model and to eliminate the uneven results of the optimization. The density of the simulated bituminous coal is 1.20 g/cm 3 , which is in the range of bituminous coal density measured in the experiment (1.2–1.5 g/cm 3 ) . Similarly, an amorphous structure containing 16 oxidized bituminous coal structures is constructed.…”

“…The density of the simulated bituminous coal is 1.20 g/cm 3 , which is in the range of bituminous coal density measured in the experiment (1.2−1.5 g/cm 3 ). 33 Similarly, an amorphous structure containing 16 oxidized bituminous coal structures is constructed.…”

Advances and Perspectives of Green and Sustainable Flotation of Low-Rank/Oxidized Coal: A Review

“…Moreover, the particle size of coal particles decreases during natural weathering so that a portion of the oxidized coal has a relatively small particle size, 15 and low-rank coals have a tendency to become ultrafine during the sorting process. 16 Fine coal represent a larger surface area and high consumption of collectors, and mechanical entrapment is another challenge.…”